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Overview of Potassium's Role in the Body

By

James L. Lewis, III

, MD, Brookwood Baptist Health and Saint Vincent’s Ascension Health, Birmingham

Last full review/revision Apr 2020| Content last modified Apr 2020
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Potassium is one of the body's electrolytes, which are minerals that carry an electric charge when dissolved in body fluids such as blood. (See also Overview of Electrolytes.)

Most of the body’s potassium is located inside the cells. Potassium is necessary for the normal functioning of cells, nerves, and muscles.

The body must maintain the potassium level in blood within a narrow range. A blood potassium level that is too high (hyperkalemia) or too low (hypokalemia) can have serious consequences, such as an abnormal heart rhythm or even stopping of the heart (cardiac arrest). The body can use the large reservoir of potassium stored within cells to help maintain a constant level of potassium in blood.

Did You Know...

  • Potassium was originally called kalium. So disorders involving potassium often have"kal" in their names.

The body maintains the right level of potassium by matching the amount of potassium consumed with the amount lost. Potassium is consumed in food and drinks that contain electrolytes (including potassium) and lost primarily in urine. Some potassium is also lost through the digestive tract and in sweat. Healthy kidneys can adjust the excretion of potassium to match changes in consumption.

Some drugs and certain conditions affect the movement of potassium into and out of cells, which greatly influences the potassium level in blood.

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